After months of demonstrations, the office of Ukraine's embattled president says he and protest leaders have called for a truce. The statement was released after violence flared Tuesday claiming at least 26 lives.

A day after deadly violence swept through Kiev, the Ukrainian state security office wasted little time in declaring that it was launching an "antiterrorist operation" across the country.

"In many regions of the country, municipal buildings, offices of the interior ministry, state security, and the prosecutor general, Army units and arms depots, are being seized," Ukraine's security chief said in a statement on the service's website. The new operation will aim to stop "a growing escalation of violent confrontation and widespread use of weapons by extremist-oriented groups."

But the "extremist picture" painted by the government – including President Viktor Yanukovych, who warned in a statement of "radical forces who are provoking bloodshed and clashes with police" – stood in sharp contrast to the makeup of the protesters who clashed with police on Tuesday.

Those demonstrators were a diverse mix of radical groups, self-defense units, retirees, entrepreneurs, and students, united in their call for President Yanukovych's resignation, if increasingly disappointed about the lack of progress during the past three months. Even as the police and crowds of protesters clashed on Wednesday morning, women passed out sandwiches, milk, and water from a safe distance, while others used hammers and pick axes to chip away concrete bricks from the square’s sidewalks, which lay in scattered stockpiles away from the front line.

“So, do we look like terrorists or extremists?” joked Katya Federenko, a recent college graduate who was helping pile stones on Independence Square, or the Maidan.

Frustration on the Maidan

Tens of thousands of street protesters have demonstrated on the Maidan since November, with a growing sense of frustration over the lack of progress during the past six weeks. Some blame opposition leaders for being politically weak, while others are pushing for a more radical action to end the civil unrest and oust the ruling elite in the hopes of ushering in an entire “reboot” of Ukraine’s political system.

Their frustrations erupted Tuesday when they realized that the ruling Party of Regions had denied opposition politicians' attempts to introduce constitutional reforms, which would bring Ukraine back to a parliamentary republic and diminish the presidential powers.

With a broad brush, Yanukovych early Wednesday morning painted all of the Maidan protesters as terrorists and extremists. The president told opposition leader Vitali Klitschko that in order to stabilize the situation, he and the other two opposition political leaders must disassociate themselves from the “radical forces” on the Maidan. The protesters on the Maidan should leave immediately and unconditionally, Yanukovych announced during late night talks with opposition leaders.

The fact that the president “still believes that people who have been willing to stand on Maidan for three months, and have been willing to risk being killed there,” would be just go home after the violence on Tuesday night shows how out of touch Yanukovych is with the current situation on the streets, said Aleksey Lushchenko, a political analyst at the Gorshein Institute, a think tank in Kiev.

But while combatants yesterday wielded sticks, stones, and Molotov cocktails against riot police, they are not easily branded simply "extremists" or "terrorists." Professors, doctors, members of nationalist Ukrainian political groups, journalists, and police officers were among the hundreds wounded and some two dozen killed in the clashes throughout the day.

The makeup of the protesters has certainly changed since demonstrations began, particularly with the arrival of units of “self-defense” groups, who began appearing in January.

Often dressed in camouflage, bulletproof vests, and ski masks, and wielding anything from baseball bats to bedposts as weapons, the groups' aim was to defend the barricades of the Maidan from the threat of riot police. But the appearance of weapons and ski masks changed the tone of the protests.

"In December, Maidan was almost like a party,” one Western official remarked last month. But by January, “the city looked like an armed camp.”

Right Sector

And even the most radical groups – such as the political party Svoboda, whose protesters commanded the Kiev City Hall until last Sunday, and Right Sector, a paramilitary outcrop of a Ukrainian nationalist civic group – are not terrorists, says Viktor Zamiatin, a political analyst at the Razumkov Center in Kiev. Though they are a step beyond the self-defense groups, with a nascent political identity, they are still simply "radicals."

“Their ideology is still being formed on the barricades right now," Mr. Zamiatin says. "But they have become an actor on the political stage. So no one can ignore them.”

Right Sector is frequently criticized by government supporters as being nationalistic Ukrainians, with anti-Semitic and anti-Russian rhetoric, an accusation its leader, Dmitry Yarush, denies.

Right Sector was formed by members of a Ukrainian nationalist group called Trizub, or Trinity. Trizub formed in 1993, shortly after Ukraine’s independence and, according to its members, engages in activities that promote the Ukrainian language, culture, and self-defense. The group hosts self-defense training camps for youths in the summer.

Mr. Yarush has said his group’s goal is to defend the Maidan, an objective they took up after riot police attacked a group of student protesters there on Nov. 30. Since then, their presence has grown more influence as their ranks have grown.

“I'm not sure if they are as radical as the Irish Republican Army, but I am absolutely sure they are not terrorists. Maybe extremists, but they are in reaction to the extreme actions of state terror,” Zamiatin says.